The Basic Functions of Harmony

At it’s core, all music can be considered an interplay of tension and release. The degree of tension can come from dissonance vs. consonance, orchestration, dynamics, or a hundred other musical elements. The key to using tension and release is balance. With too much tension and no release the tension can become unbearable and the music unlistenable. On the reverse side, if the music is too neutral with little to no amount of tension it can be dull and lifeless.

Republished Tutorial

Every few weeks, we revisit some of our reader's favorite posts from throughout the history of the site. This tutorial was first published in August of 2009.

One reason great chord progressions sound good is because they are well balanced in their use of tension and release. In this tutorial we’ll examine the very basic steps of harmonic progressions to understand how this balance works.

This tutorial assumes you have a basic understanding of music theory. You should know what notes make up what chords and understand what something like “the four chord in the key of A” means. If music theory is completely foreign to you, you may want to check out some introductory lessons before proceeding.

We’ll begin by discussing the basic functions of the three primary chords in a major key, followed by some musical examples of how these chords are used.

Understanding how certain progressions work will help you in creating your own music, but like all music theory the concepts in this tutorial are not meant to restrict you. The rules are made to be broken, but you have to be conscious that you’re breaking them before you can know if you’re doing it effectively. As Twyla Tharp writes in The Creative Habit, “Before you can think outside of the box, you have to start with a box.”

The Basic Elements

The functions of harmonic progression can be broken down into three basic elements: Tonic, Subdominant and Dominant (I, IV, and V respectively).

These three chords are the quintessential backbone of almost every song you’ve ever heard. If you play guitar, the chances are pretty good that the first three chords you learned were G, C and D and as soon as you had those three chords under your belt your song repertoire skyrocketed. Let’s take a look at what these three chords are.

Tonic

The Tonic is our home chord. It’s the I, the chord that feels solid to start on and provides a firm resolution to end on. In the key of C the Tonic is C, and it doesn’t much more complicated than that.

Subdominant

If the Tonic is home, the Subdominant (or IV chord) is like going out for a trip. You’re leaving home to discover something new, moving yourself forward in new directions. Although you could turn right back around and go home again, once you’ve set out on a journey you’re more apt to keep exploring. In the key of C the Subdominant is F.

Dominant

The Dominant (V chord) is when we’re ready to go home. Of the three, it’s the chord with the greatest amount of tension and need for release. In the key of C the Dominant is G.

A Little Theory

We can understand why the Tonic, Subdominant and Dominant chords have different degrees of tension by comparing the notes that make up each chord to the root of the key. The chords with greater dissonance against the root have greater tension.

The following chart shows this comparison:

I

IV

V

G Perfect 5, consonant

C Unison, consonant

D Major 2nd, dissonant

E Major 3rd, consonant

A Major 6th, consonant

B Major 7th, dissonant

C Unison, consonant

F Perfect 4th, dissonant*

G Perfect 5th, consonant

Consonant vs Dissonant:

3:0

2:1

1:2

*According to Persichetti, a perfect 4th is considered dissonant when in a consonant context.

The Tonic has three consonant intervals when compared to the root of the key. The Subdominant has two consonant intervals and one neutral/dissonant interval*. The Dominant has one consonant interval and two dissonant intervals.

With the most dissonant intervals, it makes sense that the Dominant would be the chord of greatest tension while the Tonic would be the chord of greatest relaxation. The Subdominant acts as a sort of middle ground, not very tense but not quite as settled as home.

Example Progressions

All this theoretical talk doesn’t do us much good if we can’t hear it being used in practice. These are all progressions you’ve heard thousands of times, but how often have you taken a moment to actually pay attention to why they’re working?

We’ll start with the most basic progression with these three chords, I IV V I. Notice the increase in tension and then the release from the G to the C in bar 4. This progression is so obvious because it has a perfect structure of build and then climax at about 3/4 of the way through.

The next progression gives us a different effect. I V IV I becomes tense more quickly and then eases out.

The IV to I cadence is not as firm or satisfying as the V to I, but it has it’s own effect. Also notice that the V chord moving to IV does not give us the same kind of build in tension as IV to V. We’re going from a chord with 2 dissonances with the Key center to a chord with only 1 dissonance. The effect is more like backing off than building up.

The 12-Bar Blues

The basic 12-bar blues is a perfect use of this concept. Here’s a typical simple blues progression:

The first four bars establish our home base. They make it clear that we’re in the key of C and C is our center. In Bar 5 we move to the IV chord and things start getting more interesting. The shift is only a little tense before settling back home at Bar 7. Then in Bar 9 we move to the V, our moment of greatest tension. Bars 9 and 10 are the climax of the piece, which relax back on our home chord of C at Bar 11.

This basic structure has been used so many times because of it’s perfect balance of storytelling. In only 12 bars we’re able to establish what we’re talking about (Bars 1-4), move the story forward (Bars 5-8), build up suspense and climax (Bars 9-10), and then round the story out and conclude back at rest (Bars 11-12).

The Jazz Blues is a common reharmonization of the basic form. Notice that although the progression may sound much fancier and more complex, the core structure of tension and release is exactly the same.

You can see now how the Tonic, Subdominant and Dominant serve as the basic structure of tension and release. All other harmony is just degrees of tension and color.

For Songwriters

Being aware of how your harmonic progressions manipulate tension and release can be a valuable tool for helping you tell your story. As an example let’s look at the first verse of Hey Jude. As if you’re not already familiar with it, here’s the basic eight-bar progression:

Here are the lyrics that land on each new chord:

C Jude

G Bad

G Sad

C Better

F Remember

C Heart

G Start

C Better

The lyrics on C, our Tonic, are “Jude”, “Better”, “Heart”, “Better”. Jude is who this whole song is about, and “Better” and “Heart” are both very positive words. They are all reinforced by the tonic.

“Remember” is telling Jude to pay attention to something important, and the IV chord works to pull us away from the I chord and grab our attention without being tense.

“Bad”, “Sad”, and “Start” are the words used on the V chord. “Bad” and “Sad” are obvious negatives, reinforced by the dominant tension. “Start” is a little more interesting. As he sings “Then you can start…” we are on the V chord, suspense has been built and we are at a high point in harmonic tension. Then when he tells us what “you can start” to do, (”make it better”) we relax and land on I. The V to I progression follows the tension and release of the lyric.

For Composers

The possibilities of how to use this manipulation of tension and release should be obvious to composers, especially those who write for film or other dramatic situations. The harmonic progression can be a solid spine for a cue, leading the listener in exactly the right places to feel greater tension and suspense or to relax and feel at ease.

Although you are generally going to want to make things a little more interesting than I IV V, the basic uses of these three chords should form the backbone that you then use other harmonies to add color and flavor to.

More Harmony Tutorials?

Did you find this tutorial interesting or useful? If you’d like to see the next stages of this concept or other tutorials on harmony, theory or composition please leave a comment to let us know.